Dental chair

ABSTRACT

Disclosed is a dental chair which can be adjusted to suit different body sizes ranging from children to average-size adults wherein the length of the backrest portion of the chair can be increased or decreased and wherein the arms of the chair are adjustable outwardly from the chair to increase the distance across the seat portion between the armrests or, if desired, the armrests can be removed.

United States Patent Inventor Fritz B. Laessker l-alrport, N.Y. Appl. No. 882,897 Filed Dec. 8, i969 Patented June 22, 1971 Assignee Sybron Corporation Rochester, N.Y.

DENTAL CHAIR 10 Claims, 4 Drawing Figs.

U.S. Cl 297/421, 297/115, 297/417 Int. Cl A47c 5/04, A47c 7/12, A47 7/54 Field of Search 297/112,

68 76 so l l as as [56] References Cited UNITED STATES PATENTS 413,156 10/1889 Wilkerson 297/116X 2,844,193 7/1958 Lauterbach 297/116 2,985,226 5/1961 Mauer et al 297/116 X FOREIGN PATENTS 818,396 10/1951 Germany 297/115 Primary ExaminerPaul R. Gilliam Attorney-Theodore B. Roessel ABSTRACT: Disclosed is a dental chair which can be adjusted to suit different body sizes ranging from children to averagesize adults wherein the length of the backrest portion of the chair can be increased or decreased and wherein the arms of the chair are adjustable outwardly from the chair to increase the distance across the seat portion between the armrests or, if desired, the armrests can be removed.

PATENTHuuuzzmn 3586374 SHEET 2 OF 3 36 86 FIG. 3

INVENTOR. FRITZ B. LAESSKER ATTORNEY PATENTED JUN22IE1YI 3 sum 3 or 3 FIG. 4

INVENTOR.

I FRITZ B. LAESSKER ATTORNEY DENTAL CHAIR BACKGROUND OF THE INVENTION The present invention relates generally to dental chairs and, more particularly to an adjustable dental chair in which the back, head and armrest can be adjusted to accommodate patients of various body sizes ranging from small children to adults.

Dental chairs of the prior art are, for the most part, not adjustable to a wide variety of body sizes. The chairs are designed primarily to accommodate the average-size adults with some provision being made to accommodate a very tall patient. For example, some dental chairs are provided with a moveable headrest which can be adjusted to accommodate the very tall patient; little or no adjustment, however, is available for accommodating the very stout or obese patient. Furthermore, the dental chairs provided by the prior art for the treatment of children are, for the most part, merely scaleddown versions of the adult chair. Accordingly, a dentist whose practice included the treatment of children, had to either install a chair specifically designed for his child patients or had to attempt treatment of the child seated in an adult chair. The latter situation is at most awkward while the former situation is expensive in that equipment especially designed for the treatment of children is warranted only where a large portion of the dentist's patients are children.

In the present invention, a dental chair is provided which can be adjusted in order to accommodate a wide variety of patient body sizes. For example, at one limit of the adjustment, the chair can comfortably and safely accommodate a child as young as 2 years of age. At the other limit of adjustment, the chair can comfortably and safely accommodate not only the normal size adult but the person who is taller than average.

SUMMARY OF THE INVENTION The dental chair of the present invention may be characterized in one aspect thereof by a provision of a back portion having guide bearings thereon for slidably containing a movable member, this movable member being slidable in the bearing to increase or decrease the longitudinal dimension of the backrest. The movable member in turn also carries a guide for slidably holding an adjustable headrest portion, both the movable member and the headrest being locked in any suitable position by a friction lock which engages the respective sliding members. In addition, the arms of the dental chair are carried by shafts which are slidably inserted into the back and seat portions of the chairs, the ,shafts being held by a detent mechanism which permits an outward adjustment of the annrests to increase the distance across the seat of the dental chair between the armrests.

OBJECTS OF THE INVENTION The primary object of the present invention is to provide a dental chair which can be adjusted to accommodate both child and adult patients.

Another object of the present invention is to provide a dental chair wherein the length of the back portion of the chair can be adjusted to accommodate patients of different heights.

A further object of the present invention is to provide a dental chair wherein the armrests are adjustable to increase the distance across the seat of the dental chair between the armrests.

Yet another object of the present invention is to provide a dental chair wherein the arm rests can be removed.

These and other objects, advantages and characterizing features of the present invention will become more apparent upon consideration of the following detailed description thereof when taken in connection with the accompanying drawing depicting the same.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of the dental chair of the present invention with the backrest and headrest partly extended;

FIG. 2 is a rear elevation view of FIG. I;

3 is a view, on a larger scale, of the back of the dental chair, partly broken away and in section showing the detachable armrests and extendable back; and

FIG. 4 is a view taken along lines 4-4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, FIG. 1 shows the adjustable dental chair of the present invention generally indicated at 10. The chair includes a seat portion 12, and a back frame 14 pivoted to the seat at 16. Slidably attached to back frame 14 is a padded backrest 18 which can be extended to increase the overall length of the back frame. Slidably connected to backrest 18 is a headrest holder 20 which can be extended to further increase the overall length of the back. Friction locks 22 and 24 (FIG. 2) are used to hold the backrest and headrest, respectively, in any extended position. Any suitable means such as a hydraulic piston and cylinder 26 may be used to power adjust back frame 14 about pivot I6 to recline the back frame.

The chair also includes a pair of adjustable armrests 28. Each armrest has one end adjustably connected at 30 to back frame 14. The other end of the armrest is supported above the seat portion of the dental chair by an armrest support member 32 which is provided with universal joints 34, 36 for connecting support member 32 respectively to the armrest and seat.

Turning to FIG. 3, a portion of back frame 14 has been broken away to expose the internal component permitting extension of the backrest and headrest holder 18 and 20 respectively. FIG. 3 shows that back frame 14 includes pairs of spaced bearing members 38 on each side of the centerline of the back frame. Each pairof bearings 38 slidably carry a rod 40 which in turn is fixed at their ends 42, 44 to backrest 18. Lifting the backrest either manually or with a hydraulic assist, slides the rods through bearing 38 to extend the padded backrest 18 from back frame 14. In the case of manual operation, friction lock 22 (FIGS. 2 and 4) carried by one of the bearing members 38 and engaging rod member 40 would be sufficient to lock the backrest 18 in any extended position.

When the power assists are not used, the backrest may be spring biased in order to balance the weight and facilitate manual lifting of the backrest. For example, each rod 40 as shown in FIG. 3 is provided with an internal bore 44. A coil spring 46 within this bore is biased between one end 48 of the bore and a shoulder 50 on back frame 14 for purposes of exerting an upward force on the backrest. A guide pin 52, fixed to shoulder 50 and extending into the bore, serves as a guide for the coil spring as backrest I8 is extended.

Padded backrest 18 carries a pair of spaced bearing members 54 which slidably support rods 56. These rods 56 carry headrest holder 20 so that sliding rods 56 through their bearing supports extends the headrest holder from backrest 18. A protective sleeve 58 surrounds the lower end 60 of rods 56 for purposes of preventing injury to the operator as the headrest holder is raised and lowered. Any suitable friction lock as indicated at 24 can be used to lock the headrest holder at the desired extended position.

Thus, with padded backrest l8 slidably carried on back frame 14 and headrest holder 20 slidably carried on the slidable padded backrest 18, the overall length of the back of the dental chair can be greatly increased. With both backrest 18 and headrest holder 20 in their lowermost position, the back will comfortably support a small child whereas moving the backrest and headrest holder to their full extended position, will increase the length of the backrest for supporting an adult person.

In order to comfortably accommodate either a child or an adult person in a dental chair, the distance between armrest 28 must also be adjustable. For this purpose, both armrest 28 of the present invention are adjustable for increasing or decreasing the distance across the seat of the dental chair between the armrests. FIG. 3 shows the adjustable armrest connection at 30 to include a sleeve member 64 at each side of back frame 14. Sleeve 64 is fixed to back frame 14 and has a series of internal detents 66 spaced axially along the internal peripheral surface of this sleeve. These detents mark the set positions to which the armrests can be adjusted. The mechanism carried by the armrests for providing this adjustment includes a hollow shaft 68 which slidably extends into sleeve 64. One end 70, of the shaft acts as a journal for supporting armrest 28. The other end 72 of the shaft has a radial opening 73 which carries a ball member 74 that can be engaged or disengaged with detents 66 for locking the armrest in a laterally adjusted position. in order to engage and release ball 74 from detents 66, an axial rod member 76 slidably extends through the hollow shaft 68. One end 78 of the rod member is formed with a pushbutton for moving the rod member axially with respect to shaft 68. The other end of rod 76 is provided with a recessed cam portion 80. Moving rod member 76 to the right, as shown in FIG. 3, drops ball 74 through opening 73 and into recess 80 to disengage the ball from detent 66. This permits the arm to be adjusted outwardly or inwardly with respect to back 14. A coil spring 82 biases rod 76 so that releasing pushbutton 78 moves the rod of the left as viewed in FIG. 3 to cam the ball through opening 73 and into the detent and lock the armrest in the adjusted position. A retaining ring 84 limits movement of the rod by spring 82. If desired, the arms can be removed completely simply by removing hollow shaft 68 from sleeve 64 and unsnapping universal 36 from seat 12 as described below.

As stated hereinabove, a universal joint 36 connects arm support 32 to the seat of the dental chair. The connection preferably is by means of a snap pin 86 which is snap-fitted into a corresponding receiver (not shown) in the chair seat. Universal joint 36 pinning arm support 32 to the chair seat and universal joint 34 connecting the armrest support to the armrest 28, not only permits adjustment of the armrest laterally outward to vary the distance between the armrests across the chair seat but also permits the armrests to remain connected to the seat portion as the back frame 14 is reclined.

Thus, it will be appreciated that the present invention accomplishes its intended objects in providing a dental chair which can be adjusted to comfortably accommodate either children or adult patients. The extendable backrest, being spring assisted, really facilitates the ease of adjusting the overall length of the backrest. A further degree of adjustment is provided by the headrest holder which is slidably carried by the backrest portion of the chair. The adjustment of thedistance across the seat between the armrests allows the arms to be moved close together to accommodate the small child or to be moved apart to accommodate the adult person. Since universal joint 36 is merely pinned to the seat of the chair, the arm can be completely removed should the dentist so desire and the mechanism for adjusting the distance between the armrests is easily operated.

Having thus described the invention in detail, what I claim as new is:

l. A dental chair having adjustable back and arms comprising:

a. a seat portion;

b. a back frame pivotally connected at one end to said seat portion;

c. a backrest slidably supported by said back frame for longitudinal movement with respect to said back frame;

d. an armrest on each side of said back frame;

e. a receiving sleeve attached to and extending inwardly from one side of said back frame and having spaced internal detent means; f. a shaft extending slidably into said sleeve and extendable outwardly therefrom, one of said armrests being attached to said shaft; and

. releasable lock means carried by said shaft and engageable with said receiving sleeve spaced intervals detent means for locking said shaft and said armrest at intervals outwardly spaced from said back frameto increase the distance between said armrests across said seat portion.

2. A dental chair as in claim 1 wherein said backrest is spring biased to facilitate movement of said backrest with respect to said back frame.

3. A dental chair as set forth in claim 1 comprising:

a. a pair of spaced bearing supports fixed to said back frame; and

b. an elongated support member slidably supported by said bearings, said support member being connected adjacent its ends to said backrest.

4. A dental chair as in claim 3 comprising friction lock means carried by one of said bearing supports and engageable with said elongated support members for locking said backrest in an adjusted position.

5. A dental chair as in claim 3 wherein said elongated support member has an axial bore and a spring in said bore biased between one end of said bore and said back frame.

6. A dental chair as in claim 5 comprising a pin fixed to said back member and extending into said bore said spring being disposed about said pin.

7. A combination as in claim 1 wherein said receiving sleeve spaced interval detent means is located along the inner periphery of said sleeve, said releasable lock means including a member for engaging said detents.

8. A combination as in claim 7 wherein said shaft has an axial bore therethrough and a radial opening through the wall of said shaft communicating with said axial bore, said releasable lock means comprising:

a. a movable member extending through said radial shaft opening for engagement with said detents;

b. a pushrod slidably retained in said axial shaft bore, one end of said rod having a recessed cam portion receiving said movable member and another end of said rod extending outwardly from said shaft;

c. bias means normally urging said rod in a direction camming said member partly through said radial shaft opening and into said detent for locking said arm in position; and

. means for urging said rod against said bias to receive said member into said cam recess and release said member from said detent.

9. A combination as in claim 1 wherein said one armrest has its second end attached to an elongated support member, and universal joints at the ends of said support member connecting said member to said arm rest and chair seat respectively.

10. A combination as in claim I comprising a headrest slidably supported by said backrest for longitudinal movement with respect to said backrest, said backrest having spaced bearings and a rod extending slidably through said bearings, said rods being connected at one end to said headrest. 

1. A dental chair having adjustable back and arms comprising: a. a seat portion; b. a back frame pivotally connected at one end to said seat portion; c. a backrest slidably supported by said back frame for longitudinal movement with respect to said back frame; d. an armrest on each side of said back frame; e. a receiving sleeve attached to and extending inwardly from one side of said back frame and having spaced internal detent means; f. a shaft extending slidably into said sleeve and extendable outwardly therefrom, one of said armrests being attached to said shaft; and g. releasable lock means carried by said shaft and engageable with said receiving sleeve spaced intervals detent means for locking said shaft and said armrest at intervals outwardly spaced from said back frame to increase the distance between said armrests across said seat portion.
 2. A dental chair as in claim 1 wherein said backrest is spring biased to facilitate movement of said backrest with respect to said back frame.
 3. A dental chair as set forth in claim 1 comprising: a. a pair of spaced bearing supports fixed to said back frame; and b. an elongated support member slidably supported by said bearings, said support member being connected adjacent its ends to said backrest.
 4. A dental chair as in claim 3 comprising friction lock means carried by one of said bearing supports and engageable with said elongated support members for locking said backrest in an adjusted position.
 5. A dental chair as in claim 3 wherein said elongated support member has an axial bore and a spring in said bore biased between one end of said bore and said back frame.
 6. A dental chair as in claim 5 comprising a pin fixed to said back member and extending into said bore said spring being disposed about said pin.
 7. A combination as in claim 1 wherein said receiving sleeve spaced interval detent means is located along the inner periphery of said sleeve, said releasable lock means including a member for engaging said detents.
 8. A combination as in claim 7 wherein said shaft has an axial bore therethrough and a radial opening through the wall of said shaft communicating with said axial bore, said releasable lock means comprising: a. a movable member extending through said radial shaft opening for engagement with said detents; b. a pushrod slidably retained in said axial shaft bore, one end of said rod having a recessed cam portion receiving said movable member and another end of said rod extending outwardly from said shaft; c. bias means normally urging said rod in a direction camming said member partly through said radial shaft opening and into said detent for locking said arm in position; and d. means for urging said rod against said bias to receive said member into said cam recess and release said member from said detent.
 9. A combination as in claim 1 wherein said one armrest has its second end attached to an elongated support member, and universal joints at the ends of said support member connecting said member to said arm rest and chair seat respectively.
 10. A combination as in claim 1 comprising a headrest slidably supported by said backrest for longitudinal movement with respect to said backrest, said backrest having spaced bearings and a rod extending slidably through said bearings, said rods being connected at one end to said headrest. 